Is CVE-2026-92597 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-92597 being exploited in the wild.

How severe is CVE-2026-92597?

Medium severity, with a CVSS score of 6.5, published 16 September 2026.

Is there a fix for CVE-2026-92597?

A patch was published on 2026-09-01: patched in version 9.1.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-92597 attacked?

It is attacked over the network.

Am I affected by CVE-2026-92597?

Check whether you run Nodemailer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-92597: Nodemailer recipient-domain validation bypass via RFC 5322 comment misparse

CVE-2026-92597 · Severity: medium · CVSS 6.5 · Published 2026-09-16

Nodemailer is a popular Node.js library for sending emails. A flaw in its email address parser allows an attacker to craft malicious recipient addresses that bypass domain validation checks and cause emails to be delivered to attacker-controlled domains. Organizations relying on Nodemailer to enforce domain allowlists or other recipient validation rules could have their emails misdirected.

Technologies: Nodemailer. Vendors: Nodemailer.

Quick answers

Is CVE-2026-92597 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-92597 being exploited in the wild.
How severe is CVE-2026-92597?: Medium severity, with a CVSS score of 6.5, published 16 September 2026.
Which products and versions are affected?: Nodemailer 6.9.16 to 9.0.6.
Is there a fix for CVE-2026-92597?: A patch was published on 2026-09-01: patched in version 9.1.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-92597 attacked?: It is attacked over the network.
Am I affected by CVE-2026-92597?: Check whether you run Nodemailer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is an Interpretation Conflict (CWE-436) in Nodemailer's RFC 5322 email-address parser. The parser incorrectly treats RFC 5322 comments (parenthesized text like "(x)") as a concatenation point for surrounding domain atoms, rather than as folding whitespace that terminates the domain. An attacker can craft a recipient address such as "user@good-corp.com(x)evil.com" which a compliant RFC 5322 parser (or allowlist checker) sees as "good-corp.com", but Nodemailer parses and routes to "good-corp.comevil.com" (a registrable attacker-controlled domain). The root cause lies in lib/addressparser/index.js where the tokenizer's "noBreak" flag causes concatenation of tokens across comment boundaries. Exploitation requires a mismatch between the application's domain validation logic and Nodemailer's parsing. The flaw has been verified end-to-end against live SMTP servers. A patch is available in version 9.1.0.

Affected products

Nodemailer Nodemailer 6.9.16 to 9.0.6

Identifiers

CVE-2026-92597
GHSA-cc9r-2j5m-2m83

Timeline

2026-09-08: disclosed
2026-09-01: patched: patched in version 9.1.0

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.